If you are wondering how long it usually takes to make profit from your affiliate site, it will depend on several factors. In fact, it is not the amount of time that matter, but the strategy you use and the consistency and focus you are giving to your affiliate site.

There are plenty of ways to do affiliate marketing, with and without a website.

If you do not have a website, the fastest way to earn commission is through Google Cash method. Simply put, start a pay-per-click campaign and send traffic to your affiliate link. Alternatively, you can buy solo ads in ezine and send traffic to your affiliate link.
How much can you make: Depend on how deep your pocket is.
Work required: Minimal

if you want to have your own web site (strongly recommend), there are few ways to do it:

One-page Leads Capture Page

Start a one page site to capture the name and email of your leads. This will allow you to follow up with them. In such cases, you will have to offer a free gift such as ebook, video, software etc to entice them to give you their particular. Once they signed up, redirect them to the merchant website.

How much can you make: Ranging from 3 figures to 4 figure income, depending on how well you generate traffic and how well the merchant’s sales copy convert.
Work required: Minimal work needed to set up website, ton of work required to generate traffic.

Blogging

Start a blog and post regularly on the product you are recommending. Do not forget to insert your affiliate links in the end of every post.
How much can you make: Ranging from few hundreds to tens of thousands, depending on how well you write, how regular you write and how useful is your content.
Work required: Blog can generate traffic by itself. Consistent posting is the key.

Build an info site

Unlike a blog, this is a full website with lots of USEFUL and VALUABLE contents. The rationale of building an info site is to establish credibility in your niche and build a close relationship between you and your reader. Once your reader trusts you and your advice, they will buy whatever you recommend.
How much can you make: Up to your imagination. If you have a group of ‘diehard’ fan, you will be able to make profit out from them over and over again.

Work required: Lot of time required initially to build content and traffic. This method is feasible if you are looking at building a long term business.

Depending on the strategy and method used, you will get different result.